From the course: CompTIA Network+ (N10-009) Cert Prep

Coaxial cabling

From the course: CompTIA Network+ (N10-009) Cert Prep

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Coaxial cabling

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- When you were a kid, I'll bet at some point you were running around the house and trying to poke behind your TV set trying to see what was back there. Well, if you did, odds are you definitely saw a coaxial cable. Now, coaxial cable is a very fascinating cable. It actually dates all the way back to World War II, one of the oldest cables of its kind. So what we're going to do in this episode is we're going to go through what a coaxial cable is, look at the parts of it, and talk about the different characteristics that you will need to know for the Net Plus. So, coaxial cable consists of several parts. Okay, actually four parts to be exact. And we're going to go over, and let's see if we can get a closeup over here. So the first part we have here is the inner conductor or the core. This actually carries the signal. Then we have an insulator. And the reason for the insulator, it has to separate the inner core inner conductor from the outer conductor here. It's made of mesh. Finally, encapsulating all this is our PVC sheath, and this provides all the durability and protection. The next characteristic of coaxial cabling is the RG or radio grade, and this determines the type of coaxial cable it is. It'll define the thickness of the cable as well as the conductors. The coaxial cable is also defined by the amount of resistance, which is measured in ohms. Be sure to know the word ohms, always like that word, ohms. It's fun to say. So if we were to talk about radio grade, we were going to talk about a cable over here and this is RG6 and we're going to go into the kind of cable it is as well as the connector. Let's take a look. So you'll notice if you can see right here, this says RG6. Now RG6 is the standard use today, folks. There used to be RG59, but that's not used anymore. So make sure for the exam you know that this is an RG6 and it has resistance of 75 ohms. Another thing we want to talk about is connectors. Now while we're here, let's talk about the two types of connectors, and this is the one type that is the most common and probably the only one you'll see today, and that is the F-type. The F-type connector is a twist on. It has a center pin that plugs into the back of a device. If you have a cable at home, if you have a cable box, it's going to plug into that device. You have to line it up and then you're going to twist this connector until it's fastened. I will tell you, these can be a hassle trying to line up the pin with a hole in the back of your device, but you'll get it. Just an important thing to remember is that it's secured in there. The next type of connector that I want to discuss is a very, very old connector called a BNC connector. So the BNC is sort of like a twist-on connector. As you can see, we have like a little bit of a maze structure has to go in and down. So that's where the twisting comes in. So you put it in, twist, and then it locks on, and to remove it, it's the reverse process. A newer, so to speak, type of connector that is definitely on the exam so make sure you know this, is called twinax. Now we talked about coax, coax being on a common axis, one inner conductor on a common axis. So it's coaxial. This is just twinax because there are two inter conductors that share an outer conductor. So let's just take a quick look if we can at twinax. So here I have an SFP, and there are various types of cables that use twinax. And what I've done, I've stripped it down and as you can see is you have two inner conductors that are twins. They share an outer conductor, and believe it or not, folks, you can actually strip down a SATA cable and see the same type of configuration with twinax. So be sure you are aware of what twinax is. The last thing I want to discuss are advantages and disadvantages of coax. The advantages are is that it's highly resistant to electromagnetic interference, and this is due to all the layers that it adds to it. Also, it is highly resistant to physical damage. You can see that this baby is pretty tough. That being said, it is also inflexible. It's very hard to install. You really got to kind of work with it, and it's also pricey. So for the exam, I want you to know the following things. Be sure that you know the radio grade of coaxial. The common one is RG6, and it has a 75 ohm impedance. The connector type is an F-type, and there's also B and C, although F-type is the much more common. Finally, be sure to understand the difference between coax and twinax.

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